London, Aug. 1: The lure of the Atkins diet, with its promise to make fat people thin if they consume enough bacon and eggs, is proving so irresistible to dieters that traditional slimming products are showing signs of floundering.

Until now, the potency of the diet has been obvious only through the huge sales of the Dr Atkins books, which now out-sell other non-fiction bestsellers by three to one.

However, when the British Potato Council began a recent offensive, saying the low-carbohydrate diet caused confusion over the vegetable’s good qualities, it was clear that the popularity of the regime was causing some anxiety.

Yesterday, in the first real sign that slimmers were now favouring the low-carb, high-fat approach, Unilever blamed the Atkins diet for thinning sales of Slim-Fast, its brand of low-calorie shakes and food. “We were caught a little bit off guard by the Atkins diet impacting our Slim-Fast sales,” said Niall Fitzgerald, chairman of Unilever.

While other brands deny that their customers are abandoning them in favour of the cream, steak and mayonnaise regime, one Internet slimming advice company said yesterday that the popularity of the Atkins diet was “bad news” for the rest of the market. “I can’t imagine they would not be worried. It is not a fad and it is not going away,” said Val Lovell, of feelingok.co.uk.

“It is incredibly easy to stick to. I imagine slimming clubs will find their numbers dropping as people discover how easy the Atkins is.”

Both Slimming World and WeightWatchers deny that the Atkins diet has had any impact on their business, although both were critical of the regime.

“We would be concerned about any diet that excludes or limits essential food groups such as carbohydrates, fruits and vegetables,” said a spokesman for Slimming World.

A spokesman for the Atkins Diet said she was unaware of the effect the regime might be having on other slimming products.

“I am sure other companies would not want to say if their sales were declining because of us,” said Jo Tomlin.